I recently had a chance to do some demo time in both a Cessna Mustang and TBM 700.  I spent an hour in the Mustang and four hours in a TBM 700 over a weekend.  Both are very capable machines and certainly worth consideration, but it was not difficult for me to decide which plane I am interested in purchasing.  I would like to get a more detailed review together when I get a bit more time, but in the meantime one of our forum contributors has a great review of the Mustang which is a thorough and comprehensive assessment of the aircraft and certainly more information than I will post.  Once a G1000 version of the TBM 850 is available I will spend some time reviewing it relative to the Mustang, but I doubt my conclusion will change since it was based on factors that are not changing from the 700 to 850.  There are a number of commercial reviews of the TBM, but I have not seen one reviewing the G1000 850 yet.  If a reader happens to know of one please link to it in forums.